The present invention relates in general to telephones, and, more particularly, to devices for preventing unauthorized use of a telephone.
Unauthorized use of telephones has, in recent years, become an extremely large source of loss to businesses as well as to telephone companies. This unauthorized use includes the placing of unauthorized long-distance telephone calls, illegal use of Watts lines or the like, or other such unauthorized uses. Often, an unauthorized user tampers with the dialing mechanism of a telephone to execute the unauthorized use. Such tampering may damage the telephone, thereby adding further costs to the costs engendered by the unauthorized use itself.
Prevention of unauthorized use of a telephone is complicated somewhat by the insistence of telephone manufacturers that nothing permanent be attached to a telephone. Thus, screws, bolts or other such mounting means cannot be used to affix a dial-locking device on a telephone.
There are telephone locking devices presently available, and the most well known of these devices is the lock cylinder used in conjunction with dial telephones. However, there are no similar devices known for use with push-button telephones.
One device for preventing unauthorized use of a push-button telephone includes a lock placed on the receiver-depressed button located in the receiver cradle. This lock keeps this button depressed even when the telephone receiver-transmitter is not accommodated in the receiver cradle. This locking device is only marginally effective because it is very easily defeated. One wishing to use a telephone equipped with such a lock merely removes the entire case section from the telephone by backing two screws in the telephone chassis out and lifting the case off that chassis. The case, along with the locking device, is thus removed and the telephone remains usable. After completion of the unauthorized use, the telephone case is simply replaced, and there is no sign of such unauthorized use.
The known devices suffer still a further drawback because such devices require the entire telephone to be disabled. If a user wishes only a single button disabled, these known devices are virtually useless. Such a situation arises when a business has an internal telephone system coupled to the usual external telephone system by depressing a particular button, such as the nine button, then dialing the external telephone number. If such a business wishes to prevent external calls on certain telephones, only the nine button need be disabled, and not the entire telephone.
There is thus a need for a telephone locking device which discourages, if not totally prevents, unauthorized use of a push-button telephone. The locking device should prove tampering or unauthorized use, and should be able to disable only a single button if so desired by a user.